Compact tree clamp

ABSTRACT

A tree clamp, especially for a tree length harvester, having a compact arrangement of a movable jaw which folds partially inside of a fixed jaw and has a pivoted section to clamp the tree. The movable jaw and its pivoted section also grasp the butt end of the tree and lift it out of the teeth of the fixed jaw at the end of the processing step. The tree is then released and free to roll into a storage rack. 
     An automatic sequence control is provided that includes a pivoted plate on the clamp which is depressed by the tree to initiate processing steps without requiring the operator&#39;s attention.

This is a division of application Ser. No. 452,171, filed Mar. 18, 1974,now U.S. Pat. No. 3,924,667.

BACKGROUND OF THE INVENTION

The invention pertains to the art of tree processors or mobile treeharvesters and especially the type referred to as tree length harvestershaving a felling head which shears a tree at the ground and holds itupright and then pivots it to a horizontal position for delimbing andtopping.

A tree length harvester of this type is disclosed in the copendingapplication U.S. Ser. No. 363,936, filed May 25, 1973, now U.S. Pat. No.3,905,407 claiming priority based on Canadian application Ser. No.:163,290 filed Feb. 6, 1973, by inventors Ian McKenzie et al and assignedto the assignee of the present invention. Its operation is in a sequencethat permits the felling head to return for a second tree while the cuttree is being delimbed and topped. This substantially reduces theover-all processing time per tree and increases the productivity of themachine.

In order to cycle the delimber while returning the felling head for asecond tree, it is necessary to clamp the tree. But no clamp hasheretofore been devised that functions properly on a tree lengthharvester and without interfering with the simultaneous processing oftrees.

DESCRIPTION OF THE PRIOR ART

One difficulty is that the tree must be transferred from the fellinghead to the clamp. The combined stack height of the felling head andclamp becomes a factor in permitting the delimber to start out closeenough to the butt end of the tree. When it fails to get behind all ofthe limbs, the trees must be partially delimbed by hand. To deal withthis problem, the clamp should be as narrow as possible. The delimbercan then be started very near the upper clamp on the felling head whenthe tree is laid in its horizontal delimbing position. This, however,requires the clamp to be very narrow.

Another problem has been the tendancy of the delimbed and topped tree tohang up after the delimber has cleared. That is, the tree is preventedfrom rolling laterally into the storage rack after being delimbed andtopped. This stops the delimber from being recycled until the tree canbe removed. Interruptions such as this cannot be tolerated in such ahigh production machine.

SUMMARY OF THE INVENTION

A compact tree clamp, especially for a tree length harvester, has afixed jaw and a movable jaw closing on the fixed jaw. The fixed jaw hasan arcuate tooth section. The movable jaw is pivoted at two locations. Afirst pivot is on the fixed jaw and allows the movable jaw to bepartially folded or collapsed into spaced frame sections of the fixedjaw. When collapsed inthis fashion, the tree is clamped in the teeth ofthe fixed jaw and prevented from axial movement by an arm of the movablejaw pivoted about a second pivot on the opposite side of the tree axisfrom the first pivot.

After delimbing and topping, the movable jaw is tilted up about thefirst pivot while the arm continues to hold the tree. This raises thebutt end of the tree and shifts it laterally toward the storage rack.The arm is pivoted about the second pivot unclamping the tree to roll itinto the storage rack.

In the application on a horizontal tree harvester, the clamp becomes afunctional part of the over-all machine when it is considered that thefelling head must transfer the tree to the clamp before delimbing canproceed and the felling head returned for a second tree.

In such a harvester, the tree clamp serves the function, not only ofsecurely clamping the tree for delimbing, but also provides thecapability of simultaneous processing which is fundamental to the highproductivity of this type of harvester.

Consistent with this objective and method of processing full lengthtrees, the present invention is viewed as a tree length harvesterautomatic sequence control including means (a pivoted plate) on themovable jaw actuated by a tree deposited on the fixed jaw, a fluidpressure source, an actuating circuit connected to said source includinga control element (sequence valve), a first cylinder for pivoting thearm of the movable jaw actuated by the control element in one positionto close the arm, means (first valve) in the actuating circuit operatedby the arm when closed initiating the delimbed cycle, a second means(second valve) operated at the end of the delimber stroke to shift thecontrol element to a second position, a second cylinder actuated in saidsecond position to tilt the movable jaw, means (third valve) operatedwhen the second cylinder is extended to cause said control element tooperate the first cylinder and to open the arm releasing the tree whichallows said first means (pivoted plate) to return causing the secondcylinder to lower the movable jaw.

In the preferred embodiment, the movable jaw will have its arm pivotedon an axis parallel to the delimber axis. The entire movable jaw is alsopivoted about a second or main pivot axis on the opposite side of thedelimber axis. The first cylinder is carried on the movable jaw and isoperable to pivot the arm about its pivot axis. The second cylinderextends between the spaced frame of the fixed jaw and is operable forpivoting the movable jaw about its main pivot axis. The arm has aninterior arc, which when closed, overlies and partially encloses thetree. The movable jaw carries the pivoted actuating plate in suchposition that as the teeth penetrate the tree, which is forced down fromabove by the arm, the plate is automatically depressed initiating thecycle.

After delimbing and topping, the movable jaw is pivoted about its mainaxis by operating the second cylinder. The actuating plate remainsengaged with the tree and in the depressed condition since the tree isstill clamped by the arm of the movable jaw. The butt end of the tree ismoved upwardly and laterally with respect to the delimber axis. At theuppermost position, the first cylinder is extended to open the arm ofthe movable jaw permitting the tree to roll down into the storage rack.This releases the actuating plate permitting the second cylinder toreturn lowering the movable jaw.

It is one advantage of the invention that the tree clamp has a dualcapability. In the one case, the tree is secured against axial movementbetween the fixed and movable jaws while in the other case it is graspedand pivoted out of the fixed jaw by the movable jaw. Thus a principaladvantage of the invention is a clamp that functions both as an axialtree clamp and tree ejection device for positive removal of the treeregardless of the slope on which the machine is operated.

Another advantage for tree length harvesters is that the clamping jawsform a compact arrangement without increasing the stack height to thedetriment of the delimber operation.

A major advantage in the over-all function of a tree length harvester isthat higher productivity is achieved because of positive ejection. Thedelimbed and topped tree is quickly and positively ejected to make roomfor the second tree after each delimbing and topping cycle.

A further major advantage is the provision of an automatic sequencecontrol for a tree length harvester in which the tree clamp initiatesthe sequence.

These and other advantages will be readily apparent by referring to thefollowing more detailed description wherein:

DESCRIPTION OF THE DRAWING

FIG. 1 is a side elevational view of a tree length harvester on whichthe tree clamp is mounted.

FIG. 1A is a partial view of the harvester depicting the motion of thefelling head;

FIG. 2 is a sectional view showing the movable jaw closed upon the fixedjaw in one position and raised in dot-dash lines taken along line 2--2of FIG. 1;

FIG. 3 is a partial plan view in the clamp showing the compact orinterleaved relationship of the jaws;

FIG. 4 is a view of the tree clamp on the side from which the tree isreleased; and

FIG. 5 is a hydropneumatic schematic of a portion of the sequencecontrol circuit.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a tree harvester 10 having front and rear sections 12, 14articulated at 15. The front section 12 has a trunnion 16 on which ispivoted a tree length processor or harvester apparatus generallyindicated by numeral 17. The apparatus 17 includes essentially a fellinghead 18, a delimber apparatus 19 a tree clamp 20 and a storage rack 21.For a more detailed description of such a harvester, reference is madeto the aforementioned application U.S. Ser. No. 363,936 now U.S. Pat.No. 3,905,407. The felling head 18 is carried on a boom 22 telescopingwithin a tubular beam 23 which pivots on the trunnion 16. The delimber19 includes a carriage 25 which cradles the tree on a bottom delimberknife (not shown) and has other delimber knives 26 which enfold about orpartially encircle the tree. Topping knives, (not shown) are also onthis carriage. The carriage 25 is pulled along a rail 27 by a cable 28as the rail itself is propelled to the rear on the beam 23 by a cableand rum drive 30. A severed tree held by the felling head 18 in asubstantially vertical position is rotated upwardly and rearwardly bypivoting the felling head on a boom arm 33 actuated by a cylinder 34(FIG. 1A). In the uppermost position the felling head positions the treebutt end in the opened tree clamp 20. The delimber knives 26 and thetopping knives of the delimber carriage 25 will also open to receive thetree. The clamp 20 must now be closed to permit the felling head toreturn for a second tree and the delimber carriage to commence itscycle. This is the position of the clamp shown in FIG. 1.

The Tree Clamp

Referring now to FIG. 2, the tree clamp 20 includes a frame 35 securedto the front of the beam 23. A goose neck portion 37 (FIG. 4) extendsupwardly in offsetting relationship toward the front of the beam so asto position the tree calmp behind the delimber carriage 25 in itsrearmost position and as close as possible to the felling head in itsraised position (FIG. 1A). The fixed jaw 38 is formed on the upperregions of spaced structural plages 40 of the frame 35 extendingtransversely over the beam 23. One side of the jaw 38 provides anarcuate tooth section 41 adjacent the delimber. The tooth sectionconforms generally to the curve of the cradle or bottom delimber knifeof the delimber carriage which will accommodate trees up to about 15inches in diameter or as small as about 6 inches on the delimber axis asdepicted at 43. A plurality of teeth 42 on the fixed jaw section 41 willpenetrate the tree to hold it securely when clamped against axialmovement.

A movable jaw 50 is pivoted at two places. A pin 53 pivotally carries anarm 51 on one side of the delimber axis and pin 54 on the opposite sidepivotally connects the entire movable jaw between the plates 40. Thepivoted arm 51 of the movable jaw is structured of a pair of elements 55(FIG. 3) having interior arcuate surfaces 56 which overlie the delimbingaxis and when folded or closed toward the tree 43, partially encircle orsurround the butt end of the tree. The elements 55 are spaced closertogether than spaced plates 57 of the movable jaw which in turn arespeced inside of the plates 40 of the fixed jaw such that the arm 51 ofthe movable jaw folds inside the plates 57 which in turn fold inside theplates 40 of the fixed jaw. The elements 55 are bushed on the pin 53carried between the plates 57 of the movable jaw while the plates 57 arebushed on pin 54 carried between the plates 40 of the fixed jawestablishing a compact or interleaved arrangement. Between the plates 40of the fixed jaw and pivotally mounted on the plates 57 of the movablejaw is an actuator plate 60 which rests above the tops of the teeth 42in the lowered position of the movable jaw being held there by a spring(not shown). The function of the plate 60 will be described more indetail hereinafter. Also mounted between the plates 40 of the fixed jawis a pair of cylinders 62, 64. Cylinder 62 is mounted between plates 40below the movable jaw. It is pivoted at its lower end at 65 and at therod end to a bracket 68 on the bottom of the movable jaw. This is thetilt cylinder. Cylinder 64 is mounted between the plates 57 of themovable jaw and is pivotally connected at 68 on its lower end and at 69on the rod end by a pin 70 carried between the elements 55 of the arm 51of the movable jaw. This is the clamp cylinder. The rod of the cylinder64 is extended in the full line position shown in FIG. 2 while the rodof the cylinder 62 is retracted. In this position the arm 51 of themovable jaw will be folded over the tree holding it firmly in engagementwith the teeth 42 on the fixed jaw. The plate 60 will be depressed belowthe tops of the teeth of the fixed jaw by the action of the tree 43being deposited by the felling head (FIG. 1A) on the fixed jaw with thearm 51 raised as depicted in dot-dash lines in FIG. 2.

Automatic Sequence Control

Referring to FIG. 5, the harvester automatic sequence control isdiagrammed insofar as it pertains to the clamp actuation and its effecton the operation of the processor 17. A source of fluid pressure 72which in the preferred embodiment is air pressure, is connected to acontrol circuit generally indicated by the numeral 74 which controls ahydraulic circuit generally shown at 75 for operating the tilt and clampcylinders 62, 64 in accordance with the processor sequence. Thehydraulic circuit 75 includes valves 76, 77 which are operated bypneumatic motors 78, 79 to direct hydraulic fluid from the pump 80 andunder pressure from the accumulator 81 to either extend or retractcylinders 62, 64 in the appropriate sequence as determined by thepneumatic control circuit 74. Hydraulic fluid is exhausted throughvalves 76, 77 to a reservoir 82.

The pneumatic control circuit 74 includes a valve 84 which is connectedto the pneumatic pressure source 72. At the point in the cycle where thedelimber has returned to the start position as shown in FIG. 1 and inreadiness to accept a tree, the valve 84 is positioned so as topressurize a portion of the circuit depicted by dash lines 85, 86 and 87and valves 88, 89 and 90. In this condition the pneumatic motors 78, 79will be vented below the piston through lines 91, 92.

When a tree is loaded on the delimber, the actuating plate 60 on themovable jaw of the clamp will be depressed by the butt end of the treeas described before. This will cause actuation of the valve 84pressurizing another portion of the circuit as depicted in dot-dashlines 93, 94, 95 pressurizing the motor 78 causing actuation then of theportion of the hydraulic circuit including valve 76 which in turn causesthe clamp cylinder 64 to extend pivoting the arm 51 down and firmlyclamping the tree into the fixed jaw. A valve 97 is hydraulicallyactuated simultaneously to start the delimber drive (not shown).

After the delimber carriage has traveled beyond the tree and the toppingknives have operated to remove the upper portion of the tree thecarriage will travel to the position of valve 98 mechanically actuatingit to energize another portion of the circuit depicted by solid lines100 and 101. A sequence control valve 102 is pneumatically actuated atthis point to pressurize lines 103 and 104 causing actuation of thepneumatic motor 79 which in turn shifts the valve 77 in the hydrauliccircuit 75 which controls the tilt cylinder 62 causing it to extendpivoting the movable jaw about pivot 54 to the position shown bydot-dash lines in FIG. 2. When this movement is completed and cylinder62 is fully extended, hydraulic pressure will be supplied at 105 to thevalve 90 in the pneumatic circuit causing it to pressurize line 107operating the pneumatic motor 78 so as to shift the hydraulic valve 76causing the cylinder 64 to retract and thus pivot the arm 51 which hasbeen holding the butt end of the tree while the movable jaw is in theraised position. This is depicted in the dot-dash lines also in FIG. 2.

At this point it will be noted by referring to FIG. 2 that the movablejaw has tilted upwardly and laterally of the delimber axis in thedirection of the storage rack 21 (FIG. 1). Thus, regardless of the slopethe harvester may be operating on the degree of incline of the movablejaw in the tilted up position will be more than enough to assure thatthe delimbed and topped tree rolls into the rack 21.

While alternate embodiments of my invention have been disclosed, it willbe understood that these descriptions are for purposes of illustrationonly and that various modifications and changes can be made to myinvention without departing from the spirit and scope of it. Therefore,the limits of my invention should be determined from the followingappended claims.

What is claimed is:
 1. A clamp for elongated objects having alongitudinal axis of substantially greater length than the largesttransverse dimension comprising a fixed jaw, a movable jaw closable onthe fixed jaw, said movable jaw having separate pivotally mountedelements, one being pivoted on one side of the longitudinal axis of saidobject and the other being pivotally mounted on the opposite side andextending transversely below the object to pivotally connect the saidone element, and means causing said elements to pivot on the said oneside of the axis and thereafter pivot the one element on the other side.2. A clamp according to claim 1 wherein said fixed jaw has spaced platesextending transversely of the longitudinal axis of said object and theelements of the movable jaw pivot between the planes of said plates. 3.A clamp according to claim 2 wherein said means includes a firstcylinder operable between said plates for pivoting both elements of themovable jaw and a second cylinder also operable between the plates forpivoting the one element.
 4. A clamp according to claim 3 wherein saidother element has spaced plates and said one element is pivoted insideof said plates.
 5. A clamp according to claim 4 wherein the spacedplates of the other element of the movable jaw pivot inside the spacedplates of the fixed jaw.